1. Field of the Invention
The present invention relates generally to intercooled cycle gas turbines. More particularly, the present invention relates to a high-pressure intercooled-supercharged cycle gas turbine with improved performance.
2. Description of the Prior Art
The capturing and reuse of exhaust gasses from gas powered engines are well documented today more than 150 years since the inception of the idea. Cogeneration and combined cycle systems, combustion turbine topping cycle and steam bottoming cycle, are the dominate systems of electricity capacity additions used today.
Other cycles based on the principle of exhaust energy recovery include the regenerative-cycle gas turbine, and the Steam Injection Gas turbine (STIG, also known as the Cheng cycle). Intercooling is sometimes used in conjunction with regeneration, intercooling regeneration being a refinement of a regenerative cycle. However, unlike the high-pressure simple-cycle gas turbine, all the gas turbine systems based on the principle of exhaust energy recovery are bulky, with engine specific power or compactness being compromised for the sake of fuel economy.
The design of Brayton-cycle (simple-cycle) gas turbines has experienced many modifications over seeking to improve the thermal efficiency and mass specific power (hereinafter collectively referred as the "performance") by concentrating on the need for compression before combustion. As exhibited hereinbelow in FIG. 1, improved performance of the turbine has been directly linked to increases in the peak cycle temperature and the corresponding increasing in the peak cycle pressure.
The great advantage of a high pressure simple cycle is that increases in peak cycle pressure toward optimum values correspond to increases in thermal efficiency, mass specific power, and working-fluid density. The simultaneous increase in thermal efficiency, mass-specific power and working-fluid density results in high performance from a compact package. However, even at the optimum high-pressure, significant enthalpy loss remains in the exhaust of a simple-cycle gas turbine.
Intercooling or intercooled compression can replace the adiabatic compression of the simple cycle. The intercooled cycle, intercooling alone without regeneration in order to maximize the power output the conventional intercooled cycle places intercooling means between compression stages of equal pressure ratio, can be considered to be a refinement of the simple cycle which produces greater power output. This conventional intercooling by itself has minimal effect on the efficiency of the turbine because additional fuel is added in the combustion chamber to produce greater net power through reduction in compression power. In fact, the thermal efficiency is often slightly lower than the simple-cycle's efficiency.
The possibility of different intercooler placement for maximum thermal efficiency under the constraint of constant peak-cycle pressure (the optimum peak-cycle pressure for a simple-cycle, for example.) and the possibility of a higher peak-cycle pressure (than the conventional optimum peak-cycle pressure for a simple cycle) for improved performance of such an intercooled-cycle have not been suggested by the prior art. It is, therefore, an object of the present invention to provide a intercooled-cycle gas turbine having intercooler placement for maximum thermal efficiency.
It is a further object of the present invention to provide a high-pressure intercooled-cycle gas turbine wherein increases in peak cycle pressure toward optimum values corresponds to increases in thermal efficiency, mass specific power, and working-fluid density.
Another object of the present invention is to provide a high-pressure intercooled-cycle gas turbine which is efficient and compact, ideally-suited for compact industrial application such as barge-mounted power plants, and marine applications
Numerous innovations for high-pressure simple-cycle gas turbines have been provided in the prior art. Eventhough these innovations may be suitable for the specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted.